Developing an Agitation Rating Scale for Horses

Written by Sharon Carroll, CHBC

I have ridden horses for over 40 years, successfully competing at 3-star eventing and grand prix dressage. I have been an Australian representative rider and an EFA Level 3 coach. My many years of coaching, from amateurs through to elite-level riders, has taught me a lot about how and why horses become agitated, and the good, and not-so-good, ways riders recognize and manage the behaviors associated with equine agitation.

In animal and human medicine and behavior science, the term “agitation” refers to excessive physical activity and/or vocalization, and is generally considered to be an indicator of some kind of stress or frustration.

Horses can become agitated for a wide variety of reasons related to distress, pain, anticipation, or frustration, including:

  • Excitement or anxiety associated with conspecifics entering or leaving the area
  • Anticipation of food
  • Preparation for serving (in the case of a stallion)
  • Disruption in the immediate environment (loud noises, unusual activity, objects moving)
  • Isolation
  • General nervousness or high levels of anxiety not related to any specific object of fear
  • Undiagnosed or untreated pain

As a CDBC and CHBC, I work with agitated and frustrated dogs and horses regularly, and I’m often struck by how similar the two species are, but also by how differently their behaviors are responded to and understood by my clients. For example, I’ve found that dog owners are much more accepting of the idea of medication for behavior, whereas horse owners have usually never even considered the possibility of such an intervention, let alone considering it an option for their horse.

My PhD research investigates the use of selective serotonin reuptake inhibitors (SSRIs) as an adjunct to a behavior modification program in horses whose behavior has been identified as dangerous or difficult to manage. Often these horses are highly anxious and reactive, and require a methodical (and often lengthy) program of desensitization and counter-conditioning, together with changes to their management and routine. In companion animals like dogs, research has shown that combining SSRIs with a behavior modification program can improve the overall result. Specifically, this combination approach can more rapidly and effectively address animal welfare issues associated with overt anxiety. (Simpson et. al 2007)

At the commencement of my PhD, there had been no papers published about the use of SSRIs as a treatment option in horses. My first project was a survey that also suggested use of SSRIs in horses was very low (compared to sedatives and tranquilizers). I found this interesting, as SSRIs have a long and successful history as non-sedating anxiolytics in humans, companion animals, parrots, and zoo species (Overall, 2004; Seibert, 2007; Durbin, 2018)

Assessing the effectiveness of a combined medication and behavior modification treatment program requires a method for objective assessment of results, which can also be used in other horses for comparison. This is why I began to look at how we could develop a relatively objective, clear, and repeatable way to measure whether a horse is having a negative experience. An agitation rating scale (used in a predetermined, fixed environment) would be one method for comparing control horses to treatment horses and comparing changes in individual horses over time.

Why a scale?

In a human hospital, scales are used for almost everything: rating pain, level of sedation, level of consciousness, level of agitation, etc.

There are a multitude of reasons for using scales, for example:

  • Assessing efficacy of treatment and adjusting as required
  • Ensuring consistent assessment across different personnel
  • Allowing a collection of individual behaviors to be grouped into a single score, instead of needing to list each and every behavior separately
  • Allowing meaningful data to be collected independently for research directly from clinical notes
  • Allowing for meaningful communication to take place between colleagues without a personal assessment of the patient or a lengthy description of all the behaviors being displayed by the patient

I view the horse agitation rating scale I am developing along with my research colleagues as a tool similar to those used in human hospitals, with similar potential uses. Right now, there are four researchers involved in the project; myself, two veterinarians, and a fellow IAABC certified horse behavior consultant, Rosa Verwijs, senior lecturer in equine behavior and nutrition at Writtle University in the UK.

What does the agitation scale look like?

This project currently only intends to develop and validate a rating scale. In order to develop and validate this agitation scale, a number of behavioral experts, and professionals from within the horse industry, will independently view video footage of 25 horses and complete a predesigned rating chart.

The horses will be assessed via video footage while wearing a halter or headstall and tied up to a rail or similar in an industry-standard manner. The filming will likely occur immediately before or after the horse’s usual daily grooming or exercise procedure. We are not planning to attempt to cause any agitation, only to observe the horses behaving in this situation in order to identify and rate behaviors that are related to agitation.

A rating chart has been developed, with 15 areas identified (e.g., tail movement, front leg movement, defecation, etc.); each of these areas is further divided into two or three categories of behavior within that area. The pilot testing of this scale is underway at the moment.

In the project, ten observers from various backgrounds within the horse industry, such as veterinarians, trainers, riders, and farriers, will independently watch the videos. The observers will circle behaviors on the agitation rating chart whilst observing the footage. Each observer will also indicate their opinion as to whether they believed overall that the horse was displaying low, moderate, or high levels of agitation. Three equine behavior experts (CHBCs or veterinary behaviorists) will also independently view the footage of each horse and give their expert opinion as to the agitation level of the horse. The calculated results from the charts will be compared to the observers’ overall impressions and also to the expert opinions.

Essentially, we are just trying to determine if we can create a behavior chart that is simple enough, and has enough clarity, that a collection of people of varying backgrounds can confidently use the chart. We are then trying to test inter-observer variation and intra-observer variation (i.e., does each observer score the same for a particular piece of footage? When an observer is presented with the same piece of footage at a later date, do they still give the same score they gave previously?). Ultimately, the scale could be useful to assess the effects of dissimilar environments on behavior.

It was a discussion early in the project as to whether it should be an “arousal rating scale” or an “agitation rating scale,” given that arousal more accurately defines both positive and negative valance of emotions. However, it was decided that the correct term for this scale would be “agitation.” This is because even if the root cause of the emotion is positive — for example if the horse is looking at a bucket of feed or watching nearby conspecifics running free, or in the case of a stallion, watching a mare being prepped for serving — the behaviors displayed are based on frustration,  in that the horse is tied up and can’t reach the feed bucket, or can’t perform the behaviors it would typically undertake when faced with the stimuli.

Uses for an agitation scale

Although the reason I started looking at developing an agitation rating scale for horses was to assess whether behavior modification and SSRI treatment were having a positive effect on horses with behavior issues, such a scale could have a wide variety of different uses.

Veterinary and behavior professionals

It is imperative to remember, though, that this is just a rating scale of demonstrated behaviors in a horse that is tied up. It would always be up to an expert to determine if the level of agitation is appropriate under the given circumstances, or what underlying issues the agitation may be indicating in terms of possible pain, lack of exercise or stimulation, inappropriate diet, inappropriate management or housing, inappropriate training or handling, or simply in an overly stimulating environment at the time.

If an inexperienced horse owner assessed their horse using this scale and reported to me as a behavior consultant that the results indicated high levels of agitation, I would want to ask questions such as:

  • Is this type of behavior new for this horse?
  • What was happening in the surrounding area when you undertook the assessment?
  • How long has the horse lived at their current location?
  • Has anything changed recently for the horse?
  • What is the horse’s daily and weekly routine with regard to exercise?
  • How is the horse housed? Are they stabled all the time, in a stable and paddock, or a paddock only?
  • What is the horse’s diet?
  • How many different people ride or handle the horse?

If, for example, after further discussion with the owner I identified that this behavior was specifically associated with the owner starting to get tack ready to tack up and ride, this would cause a different concern to me than a horse that demonstrated this behavior only when feed was being prepared in an adjacent area.

Of course, it should be remembered too that a horse that is assessed as showing low levels of agitation should not automatically be classified as a comfortable, satisfied and relaxed horse with no welfare issues. Horses that are very sick, in immense pain, and/or compromised by learned helplessness could still demonstrate behaviors indicative of low levels of agitation.

Horse owners, buyers, and riders

An inexperienced horse owner may not recognize agitated behaviors as “abnormal.” Hence horses may be experiencing pain, anxiety, fear, or frustration, without the owner being concerned about these issues. A tool such as this rating scale would allow an inexperienced horse owner to undertake a two-minute observation period and then calculate the results. Hence a scale such as this agitation rating scale may result in an inexperienced owner becoming aware that their horse’s behavior is indicative of moderate or high levels of agitation. As a result, the owner may decide to seek assistance to address the underlying issues; ideally they would seek out help from a behavior consultant and veterinarian.

Pre-purchase assessment is another possible use for this type of chart. An example would be to use a fixed setting (i.e., in a defined quiet environment, or in a defined busy environment, or upon immediate arrival at a horse competition or new environment). In this way an individual horse’s behavior could be assessed in an objective way in a fixed setting. For example, a horse that arrives at a competition, or into a new and stimulating environment, and scores at a low agitation level requires a different handler skill level than a horse that demonstrates behaviors associated with a high level of agitation.

Of course, there are a range of other factors to consider, and the same horse with further training and experience may score differently at a later date. However, agitation levels do give an indication as to the skill level the handler would need to manage the horse in a similar setting in the immediate future. Sometimes this type of assessment (i.e., the behaviors displayed by a horse left tied to single point for two minutes) offers more information than viewing the horse being ridden. This is because the rider’s skill can have a significant impact on whether the horse appears calm and quiet, and thus easy to manage.


As humans, we still have a lot to learn about animal emotion, cognition, and mental health. Participants in animal sports, like myself, have a duty to work with our partner animals, to understand their needs, and to work within their cognitive abilities to ensure they genuinely benefit from the entire experience, not just comply to our needs. There is no doubt my approach to dogs and horses improved immensely during my studies involving the training of zoo species in a protected contact setting. This setting forces you to ensure that the animal benefits from participation in training; the option of relying on any type of force is taken away, and you have to be able to really think from the animal’s perspective.

It is a daily learning curve, and I am deeply committed to furthering my understanding of the learning process across species, but in particular my ability to identify and manage animals with psychological or emotional issues. Developing tools to gather clear data is an important part of making sure that how we’re choosing to treat these issues is actually benefitting the animal. That’s what I’m doing with this agitation rating scale project, and I hope that it will be a useful addition to the equine behaviorist’s toolbox


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Overall, K. (2004). Paradigms for pharmacologic use as a treatment component in feline behavioral medicine. Journal of Feline Medicine and Surgery 6:1, pp.29-42.

Poulsen, E.M.B. et. al (1996). Use of fluoxetine for the treatment of stereotypical pacing behavior in a captive polar bear. Journal of the American Veterinary Medical Association 209:8, pp. 1470-1474.

Seibert, L.M. (200). Pharmacotherapy for behavioral disorders in pet birds. Journal of Exotic Pet Medicine 16:1, pp. 30-37.

Simpson, B. et. al, (2007). Effects of Reconcile (Fluoxetine) chewable tablets plus behavior management for canine separation anxiety. Veterinary Therapeutics 8:1, pp. 18-31.